package com.netty.esc.Interceptor.filter;

import com.alibaba.fastjson.JSON;
import com.netty.esc.common.base.HttpStatusCodeEM;
import com.netty.esc.common.base.BaseResponseDTO;
import com.netty.esc.utils.JwtToken;
import lombok.extern.slf4j.Slf4j;
import org.apache.shiro.authc.AuthenticationException;
import org.apache.shiro.web.filter.authc.BasicHttpAuthenticationFilter;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;

@Slf4j
public class JwtFilter extends BasicHttpAuthenticationFilter {

    //是否登录尝试
    @Override
    protected boolean isLoginAttempt(ServletRequest request, ServletResponse response) {
        HttpServletRequest req = (HttpServletRequest) request;
        String authorization = req.getHeader("Authorization");
        return authorization != null;
    }

    /**
     * 第一步  判断请求是否登录
     * 这里我们详细说明下为什么最终返回的都是true，即允许访问
     * 例如我们提供一个地址 GET /article
     * 登入用户和游客看到的内容是不同的
     * 如果在这里返回了false，请求会被直接拦截，用户看不到任何东西
     * 所以我们在这里返回true，Controller中可以通过 subject.isAuthenticated() 来判断用户是否登入
     * 如果有些资源只有登入用户才能访问，我们只需要在方法上面加上 @RequiresAuthentication 注解即可
     * 但是这样做有一个缺点，就是不能够对GET,POST等请求进行分别过滤鉴权(因为我们重写了官方的方法)，但实际上对应用影响不大
     */
    @Override
    protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) {
        HttpServletRequest httpServletRequest = (HttpServletRequest)request;
        String requestURI = httpServletRequest.getRequestURI();
        System.out.println(requestURI);
        log.info("JwtFilter-->>>执行登录认证:init()");
        //如果请求头不存在token,则可能是执行登陆操作或是游客状态访问,直接返回true
        if (!isLoginAttempt(request, response)) {
            return false;
        }
        //如果存在,则进入executeLogin方法执行登入,检查token 是否正确
        try {
            executeLogin(request, response);
            return true;
        } catch (Exception e) {
            e.printStackTrace();
            throw new AuthenticationException("Token失效请重新登录!");
        }
    }

    /**
     * 重写AuthenticatingFilter的executeLogin方法丶执行登陆操作
     */
    @Override
    protected boolean executeLogin(ServletRequest request, ServletResponse response) throws Exception {
        log.info("JwtFilter-->>>executeLogin-Method:init()");
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        String token = httpServletRequest.getHeader("Authorization");//Access-Token
        JwtToken jwtToken = new JwtToken(token);
        //UsernamePasswordToken usernamePasswordToken = new UsernamePasswordToken(UserCache.getCurrentUser().getTelephone(),UserCache.getCurrentUser().getPassword());
        // 提交给realm进行登入,如果错误他会抛出异常并被捕获, 反之则代表登入成功,返回true
        getSubject(request, response).login(jwtToken);
        return true;
    }


    /**
     * 对跨域提供支持
     */
    @Override
    protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        httpServletResponse.setHeader("Access-control-Allow-Origin", httpServletRequest.getHeader("Origin"));
        httpServletResponse.setHeader("Access-Control-Allow-Methods", "GET,POST,OPTIONS,PUT,DELETE");
        httpServletResponse.setHeader("Access-Control-Allow-Headers", httpServletRequest.getHeader("Access-Control-Request-Headers"));
        // 跨域时会首先发送一个option请求，这里我们给option请求直接返回正常状态
        if (httpServletRequest.getMethod().equals(RequestMethod.OPTIONS.name())) {
            httpServletResponse.setStatus(HttpStatus.OK.value());
            return false;
        }
        return super.preHandle(request, response);
    }

    /**
     * 当isAccessAllowed 判断请求未登录后会走本方法
     * 这里的功能是是否拒绝掉当前请求，现在全都拒绝了，返回未登录状态码，后续可以进行自由拓展
     * */
    @Override
    protected boolean onAccessDenied(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletResponse httpServletResponse = (HttpServletResponse)response;
        httpServletResponse.setHeader("Access-Control-Allow-Origin", "*");
        httpServletResponse.setHeader("Cache-Control", "no-cache");
        httpServletResponse.setCharacterEncoding("UTF-8");
        httpServletResponse.setContentType("application/json");
        PrintWriter writer = httpServletResponse.getWriter();
        writer.write(JSON.toJSONString(BaseResponseDTO.setResult(HttpStatusCodeEM.TOKEN_ERROR)));
        writer.close();
        return false;
    }
}
